High Mountains

[Dekan]

The highest mountain in the world today, is of course Mt. Everest. This is a bit over 29,000 feet.

 

I wonder whether in past ages, there were even higher mountains, and how high they were.

 

The shape of continents which existed in the past, can be found out, and described to us, by modern geologists.

 

Can geologists also ascertain what height mountains were in the past? Were there any "super-Everests"?

[Brainteaserfan]

The highest mountain in the world today, is of course Mt. Everest. This is a bit over 29,000 feet.

 

I wonder whether in past ages, there were even higher mountains, and how high they were.

 

The shape of continents which existed in the past, can be found out, and described to us, by modern geologists.

 

Can geologists also ascertain what height mountains were in the past? Were there any "super-Everests"?

...Highest from sea level. Mt Chimborazo is the highest above earth's center.

http://geology.com/records/highest-mountain-in-the-world.shtml

[Dekan]

...Highest from sea level. Mt Chimborazo is the highest above earth's center.

http://geology.com/r...the-world.shtml

 

Thanks Brainteaser for the link - I didn't know about Chimborazo. But measuring things from the Earth's centre, seems a bit weasely, if you'll forgive me for saying so! We've no direct experience of where the Earth's centre is. Our only experience is of the land, or the sea-bottom, so we should make measurements from these. If we measure from these, how high can a mountain get?

 

Presumably there's a maximum height it can reach. Before it starts crumbling under its own weight.

 

For instance, could an Earth mountain reach 50,000 feet above sea-level, or 70,000 feet. Was there such a mountain in past geological times, and have geologists found one?

[Ophiolite]

You are correct that there is a maximum height. This may be determined, as you suggest, by the strength of the rock from which it is made. A second factor is isostasy. As the mass of the mountain increases its roots get pushed further into the mantle, so that it tends to sink.

 

I don't know what the limit is from either of these mechanisms, but I believe I have read it is of the order of 50,000', certainly not much more. It is extremely difficult to assess the height of past mountain ranges. One possible way of estimating may lie in looking at mountain roots that have subsequently been exhumated. Their mineralogical composition can tell us what pressure and temperature regimes they experienced and thus how deep they must have been and thus how high was the rock pile above them. I do not know of any published work on this. There would certainly be large error bars on numbers that were determined this way.

[Moontanman]

According to planetdesigner.com the maximum mountain height on the Earth should be in the neighborhood of 16570m (54,000'), on the moon it would be 124,000m or so. I'm not sure if that is figured as above sea level or from the center of the earth but having part of the mountain under water should allow for more height or would it? I'm not sure if the support of water would be significant to a mountain.